System for Rotating Products Having an Irregular Geometrical Shape

ABSTRACT

A system for rotating products ( 11 ) having an irregular geometrical shape, comprising a rotation system comprising a retaining part with a plurality of individually movable rods ( 2 ) adapted to engage a product ( 11 ), thereby at least substantially fixing the product ( 11 ) relatively to the retaining part, and means ( 8 ) for rotating the retaining part, and thereby a fixed product ( 11 ), with an individually determined rotational angle about a rotational axis. The system further comprises means for determining the orientation of each product ( 11 ) upon arrival at the system. A control system controls the rotation system and is operatively connected to the determining means. The control system is adapted to determine the rotational angle based on the orientation, and to control the rotation system accordingly. 
     In a method for rotating a product the orientation of the product is determined, e.g. by means of a vision based technique, and the product is rotated to a desired orientation.

FIELD OF THE INVENTION

The present invention relates to a system for rotating products havingan irregular geometrical shape, wherein the products may be rotated byan individually determined rotational angle. The individual rotationalangle may be determined on the basis of the orientation of a productwhen it arrives at the system.

The invention further relates to a transport system comprising a systemas described above and a method for rotating products having anirregular geometrical shape.

BACKGROUND OF THE INVENTION

Processing lines for processing products often require that the productsarrive in a predetermined position and/or orientation, in order to allowfor automatic further processing or manual processing at anergonomically optimal position.

A number of rotation units exist which are suitable for rotatingproducts having a uniform and regular geometrical shape. These areapplied in many places, e.g. in front of automatic palletizing systems,where rotation of the products may assist in creating a desired patternof products on the resulting pallet. Thereby the pallet is utilized tothe greatest extent possible, and it is relatively stable, since astabilizing bond is formed between the individual layers on the pallet.

Such rotation units are often provided with a lifting unit being movablefrom beneath and a retaining unit movable from above. Thereby theproduct can be rotated while it is raised above the conveying means byrotationally driving the lifting unit and/or the retaining unit.

Rotation of products having an irregular geometrical shape may berequired in processing lines applied within a number of variousindustries, e.g. the food industry, such as in slaughterhouses.

With increasing automation and focus on ergonomics in slaughterhouses itis important that products, such as pieces of meat from an animalcarcass, arrive at the subsequent process in a processing lineorientated and positioned in a correct manner, thereby allowing anautomatic process to be performed with an optimal yield, or allowing amanual process to be performed in an ergonomically correct manner.

A subsequent process can, e.g., be automatic derinding, where the lardportion of the meat is cut away, and a correct positioning of theproduct relatively to the derinding equipment is crucial for a correctprocessing with a high yield. At the present time the products arepositioned manually in front of the derinding equipment.

Another subsequent process can be hanging product pieces on rodsprovided with hooks (so-called ‘christmas trees’) for furthertransportation or intermediate storage. At the present time the productpieces are rotated manually in order to make it possible to hang them onthe rods with hooks (christmas trees). This is manually demanding sincesuch products pieces are normally very heavy.

Slaughterhouses impose increasing demands on correct orientation andpositioning of product pieces relatively to the subsequent process inthe processing line in order to allow an automatic process to beperformed in an optimal manner, or in order to allow a manual process tobe performed in an ergonomically optimal manner.

At the same time it is required that equipment for processing productsis hygienic, and that cleaning of the equipment can be performed easily,i.e. with a small effort and incurring low costs.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a system for rotatingproducts having an irregular geometrical shape, the system being capableof ensuring a correct positioning and orientation of an arriving productbefore it is passed on for further processing.

It is a further object of the invention to provide a system for rotatingproducts having an irregular geometrical shape which improves theergonomics of a possible manual further processing of the product,relatively to existing systems.

It is an even further object of the present invention to provide atransport system for handling products having an irregular geometricalshape, wherein the required manual contribution is minimised.

According to a first aspect of the invention the above and other objectsare fulfilled by providing a system for rotating products having anirregular geometrical shape, the system comprising:

-   -   a rotation system comprising a retaining part with a plurality        of individually movable rods adapted to engage a product,        thereby at least substantially fixing the product relatively to        the retaining part, and means for rotating the retaining part,        and thereby a fixed product, with an individually determined        rotational angle about a rotational axis,    -   means for determining the orientation of each product upon        arrival at the system, and    -   a control system for controlling the rotation system, said        control system being operatively connected to the determining        means, the control system being adapted to determine the        rotational angle based on said orientation, and to control the        rotation system accordingly.

According to a second aspect of the invention the above and otherobjects are fulfilled by providing a method for rotating a product, themethod comprising the steps of:

-   -   determining the orientation of a product,    -   comparing the orientation of the product with a desired        orientation,    -   based on said comparison, determining a rotational angle        necessary to obtain the desired orientation, and    -   rotating the product in accordance with the rotational angle.

The step of rotating the product preferably further comprises the stepsof:

-   -   moving a retaining part comprising a plurality of rods into        engagement with the product, thereby at least substantially        fixing the product relatively to the retaining part, and    -   rotating the retaining part in accordance with the rotational        angle.

Since the arriving products, when applying the system and/or the methodaccording to the invention, are rotated to a desired position andorientation in an automatic manner, the required manual processing stepsare reduced considerably, and improved ergonomics are thereby obtained.Simultaneously it is obtained that the products are positioned in such amanner that the yield of subsequent automatic or manual processes isoptimised.

The rotation system comprises means for engaging the products. This may,e.g., be one or more rods, e.g. at least substantially vertical rods,which may be arranged in a row. In a preferred embodiment the row ofengaging means, preferably the rods, form an oval, circular or polygonalperiphery, thereby allowing the engaging means to act on the productfrom a number of various directions.

Each of the rods may be movable in at least substantially mutualparallel directions. In a preferred embodiment the product which is tobe rotated rests on an at least substantially horizontal plane surface.In this case the rods may advantageously be movable in an at leastsubstantially vertical direction, i.e. they are movable in a directionwhich is at least substantially normal to a plane defined by the surfaceupon which the product rests. Alternatively the direction of movement ofthe rods may form any other suitable angle with the surface upon whichthe product rests.

The rotational axis may also be at least substantially parallel to thedirection of movement of the rods.

In a preferred embodiment the rods are arranged in such a way that theirend parts form a pattern, said pattern comprising at least part of atleast one circle. This pattern may, e.g., be one or more full circlesand/or one or more parts of one or more circles. A part of a circle may,e.g., be a semicircle, a quarter of a circle, or a part covering anarbitrary desired angular part of a circle. In case two or morecircles/parts of circles are present, these may be arranged in such away relatively to each other, that at least part of at least two atleast substantially concentric circles are formed. Alternatively, thecircles may be arranged in such a way that the circles are completelynon-overlapping, or in such a way that they intersect or are tangent toeach other.

Thus, in a preferred embodiment a row of rods are arranged at leastsubstantially vertically in a circle, in such a way that the product isretained in an at least substantially vertical position by at least twoguide disks having guide holes for the rods. The guide disks arepreferably fixedly mounted at least substantially perpendicularly to anat least substantially vertical rotational axle, in such a way thatrotating the axle results in an at least substantiallyhorizontal-rotation of the guide disks, and thereby a rotation of thevertical rods about a centre point of the circle which they define. Whenapplying multiple rows of rods, these are arranged in at leastsubstantially concentric circles. The system may advantageously bepositioned above a conveyor.

The dimension(s) of the circular row(s) where the rods are mounted, aswell as the amount of circular rows and the amount of rods in thecircular row(s) will depend on the product(s) which is/are to berotated. When using multiple at least substantially concentric circularrows of rods, products with large mutual variations in terms ofgeometrical dimensions may be rotated.

Alternatively, the rods may be arranged in such a way that their endparts form any other pattern, such as an oval, a polygon, a straightline, a star, and/or parts of one or more such patterns. The rods mayeven be randomly distributed across a given area.

The system may further comprise means for moving the rods. The means formoving the rods may be adapted to move each of the rods in an at leastsubstantially vertical direction, e.g. as described above.

In a preferred embodiment the means for moving the rods comprises an endpart mounted on each of the rods and at least one lifting part adaptedto engage at least some of the end parts in order to move at least someof the rods.

An end part may, e.g., be a ring or a cylinder shaped disk having alarger outer diameter than the rods. The lifting part may in this casecomprise a lifting ring having an outer diameter which is smaller thanthe diameter of a circle or a part of a circle defined by the rods, butlarger than the diameter of the circle defined by the inner part of therings/disks which are mounted on the corresponding rods. This liftingring may thereby engage a number of rings/disks, and when the liftingring is moved upwards the rods will accordingly also be moved upwards.

In case the rods form at least part of two concentric circles, the innerdiameter of the lifting ring must be larger than the outer boundarycircle of the inner row of vertical rods, and smaller than the outerboundary circle of the end rings/disks mounted on the vertical rods.Thereby one lifting ring can simultaneously engage end rings/disksassociated with both circles, and it is therefore possible to lift rodsfrom both circles simultaneously. Similarly, further rows of rods may bemounted in such a way that one lifting ring is provided for each tworows of rods.

The retaining part may further comprise means for controlling theorientation of the rods. The means for controlling the orientation ofthe rods may be adapted to maintain the rods in an at leastsubstantially vertical orientation.

The lifting ring(s) may, thus, advantageously be provided with at leastsubstantially vertical guides and at least substantially verticalraising/lowering means. The lifting ring(s) is/are arranged above anupper guide disk and below the rings/disks mounted on the rods. When thelifting ring(s) is/are raised the rods will accordingly also be raised,since they are carried by means of the lower part of the mounted endrings/disks.

When the lifting ring(s) is/are lowered the rods will accordingly alsobe lowered due to gravity. If one or more of the rods touches a productpositioned on the conveyor arranged beneath the system before thelifting ring is at its lowermost position, lowering of this/these rod(s)will be stopped, and it/they will remain resting on the product, whilethe remaining rods will continue to their lowermost position. Theproduct will thereby be fixed between a certain number of rods, in sucha way that the product will rotate along when the rotational axle withthe fixedly mounted guide disks is rotated. The rotation is stopped whenthe product is in a predetermined position, and the lifting ring israised along with the vertical rods to an uppermost position, and theproduct on the conveyor may be transported further on in the processingline. The rotational axle may advantageously be at least substantiallycontinuously rotatable, thereby allowing any desirable rotational angleto be obtained. Thereby the product may be rotated exactly to thedesired position.

In any of the embodiments described above the rods may preferably bemoved by means of at least one actuator. The actuator is preferably avertical actuator adapted to raise/lower the rods in an at leastsubstantially vertical direction.

The system may further comprise a conveyor for receiving a product, theconveyor preferably being positioned below the rotation system. In thiscase the rotation system may be adapted to be lowered onto an arrivingproduct, thereby causing retaining and rotation of the product.

The means for determining the orientation of each product may compriseoptical means, such as a camera. Determining the orientation of theproducts may, thus, advantageously be performed by means of so-calledvision based techniques.

The system of the invention may advantageously form part of a transportsystem, e.g. a transport system forming a part of a processing line,such as a processing line in a food company, such as a slaughterhouse.Such a transport system further comprises at least one conveyorpositioned upstream relatively to the system, and at least one conveyorpositioned downstream relatively to the system, in order to allowproducts to be led to and from the system without the requirement ofmanual steps.

In the present context the term ‘upstream’ relatively to a given pointin a processing line should be interpreted as a point in the processingline which a product, during normal operation, would arrive at before itarrives at the given point. Analogously, the term ‘downstream’ should beinterpreted as a point which the product would arrive at after itsarrival at the given point.

The arriving products may have a regular sequentially predefinedpositioning so that the rotational angle of the products can beestablished beforehand and supplied to the control means of the rotationsystem in order to ensure correct positioning of the products forsubsequent processing. The stop position of the products beneath therotation system may be determined on the basis of a detection of thefront edge or the rear edge of the product, and based on empiricalvalues the stop position may be calculated there from.

The products may arrive randomly positioned, and a detection at arrivalat the rotation system detects this position, and the control algorithmcan calculate the rotational angle of the individual product, therebyensuring correct positioning of the product in the subsequent processingline. The detecting system may comprise a vision recording of anarriving product which is compared to a desired positioning. Based onthis the rotational angle and the position where the product must stopunder the rotation system are calculated. It is desired that the stopposition is the position where the centre of gravity of the product isat the centre of the rotational movement, since this results in an idealrotation.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further described with reference to theaccompanying drawings in which

FIG. 1 is a top view of the rods with lifting ring and guide disks,

FIG. 2 is a cross sectional view of a preferred outline of the rotationsystem along the line A-A of FIG. 1 with the rods and the lifting ringin a raised position,

FIG. 3 is a cross sectional view of a preferred outline of the rotationsystem along the line A-A of FIG. 1 with the rods and the lifting ringin a lowered position,

FIGS. 4A, 4B and 4C schematically and sequentially illustrate rotationof a product having an irregular geometrical shape, and

FIG. 5 schematically illustrates rotation of sequentially arrivingproducts.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of the rotation system with guide disks 1 andvertical rods 2 arranged in a circular row. In the Figure the end piecesof the vertical rods 2 form two concentric circular rows. Furthermore, alifting ring 3 for moving the vertical rods 2 in an at leastsubstantially vertical direction is shown.

FIG. 2 is a side view of the rotation system, corresponding to a crosssection along the line A-A in FIG. 1. For the sake of clarity, FIG. 2only shows the rods 2 which are positioned in the right and left sidesof the cross section, respectively. It should, however, be understoodthat the remaining rods 2, as shown in FIG. 1, are also present in thesystem shown in FIG. 2. The vertical rods 2 have been raised to an upperposition by lifting ring 3 which carries the vertical rods 2 by means ofthe mounted end rings/disks 4. Lifting ring 3 is moved by means ofactuator(s) 5, and its vertical movements are controlled by guides 6.The guide disks 1 are fixedly connected to a rotating axle 7, which isconnected to a drive unit 8. Beneath the rotation system a conveyor 9for conveying the product pieces is mounted.

FIG. 3 shows the rotation system with the lifting ring 3 in a lowerposition, and the vertical rods 2 have been lowered to the level of theconveyor 9 due to gravity.

FIGS. 4A, 4B and 4C sequentially illustrate rotation of a product 11having an irregular geometrical shape. The product 11 arrives in FIG. 4Aon a preceding conveyor 12. The front and rear edges of the product 11are detected by a detector 10 during conveying from conveyor 12 toconveyor 9, i.e. while the product 11 is moved to a position beneath therotation system. The product 11 is stopped beneath the rotation systembased on a calculation or a previously empirically determined positionas shown in FIG. 4B. The lifting ring 3 is lowered, and the verticalrods 2 are lowered due to gravity. During this operation some of therods 2′ will remain resting on the product 11, and are therefore unableto continue the lowering movement to the lower position. Other rods 2,which are not inhibited by the product 11, are lowered to theirlowermost position. Some of the rods 2′ thus resting on the product 11,while other of the rods 2 are positioned beside the product 11, causesthe product 11 to be retained by the completely lowered rods 2 during asubsequent rotation of the rotation system, and the product 11 willthereby rotate along when the rotation system is rotated. Thereby arotational angle is obtained for the product 11 which is equal to theangle which the rotation system is rotated through.

The guide disks 1 are rotated through the predefined or calculatedrotational angle by drive unit 8. Thereby the positioning of the product11 after the rotation will be correct relatively to the subsequentprocessing.

FIG. 5 shows an example of products 11 arriving sequentially positioned.In this example, the products 11 arrive with every second product 11positioned in the same manner. The products 11 leave the rotation systemon conveyor 13 positioned in a manner which is desired for thesubsequent processing of the products 11.

1. A system for rotating products (11) having an irregular geometricalshape, the system comprising: a rotation system comprising a retainingpart with a plurality of individually movable rods (2) adapted to engagea product (11), thereby at least substantially fixing the product (11)relatively to the retaining part, and means (8) for rotating theretaining part, and thereby a fixed product (11), with an individuallydetermined rotational angle about a rotational axis, means fordetermining the orientation of each product (11) upon arrival at thesystem, and a control system for controlling the rotation system, saidcontrol system being operatively connected to the determining means, thecontrol system being adapted to determine the rotational angle based onsaid orientation, and to control the rotation system accordingly,wherein the rods (2) are arranged in such a way that their end partsform a pattern, said pattern comprising at least a part of at least onecircle.
 2. A system according to claim 1, wherein each of the rods (2)is movable in at least substantially mutual parallel directions.
 3. Asystem according to claim 2, wherein the rotational axis is also atleast substantially parallel to the direction of movement of the rods(2).
 4. (canceled)
 5. A system according to claim 14, wherein the rods(2) are arranged in such a way that their end parts form a pattern, saidpattern comprising at least parts of at least two at least substantiallyconcentric circles.
 6. A system according to claim 1, further comprisingmeans for moving the rods (2).
 7. A system according to claim 6, whereinthe means for moving the rods (2) is adapted to move each of the rods(2) In an at least substantially vertical direction.
 8. A systemaccording to claim 7, wherein the means for moving the rods (2)comprises an end part mounted on each of the rods (2) and at least onelifting part adapted to engage at least some of the end parts in orderto move at least some of the rods (2).
 9. A system according to claim 6,wherein the means for moving the rods (2) comprises at least oneactuator.
 10. A system according to claim 1, wherein the retaining partfurther comprises means (1) for controlling the orientation of the rods(2).
 11. A system according to claim 10, wherein the means (1) forcontrolling the orientation of the rods (2) is adapted to maintain therods (2) in an at least substantially vertical orientation.
 12. A systemaccording to claim 1, further comprising a conveyor (9) for receiving aproduct (11), the conveyor (9) being positioned below the rotationsystem, and wherein the rotation system is adapted to be lowered onto anarriving product (11).
 13. A system according to claim 1, wherein themeans for determining the orientation of each product (11) comprisesoptical means.
 14. A system according to claim 13, wherein the opticalmeans comprises a camera.
 15. A transport system comprising a systemaccording to claim 1, at least one conveyor positioned upstreamrelatively to the system, and at least one conveyor positioneddownstream relatively to the system.
 16. A transport system according toclaim 15, said transport system forming part of a processing line.
 17. Amethod for rotating a product, the method comprising the steps of:determining the orientation of a product, comparing the orientation ofthe product with a desired orientation, based on said comparison,determining a rotational angle necessary to obtain the desiredorientation, moving a retaining part comprising a plurality of rods intoengagement with the product, thereby at least substantially fixing theproduct relatively to the retaining part, and rotating the product inaccordance with the rotational angle, thereby rotating the product inaccordance with the rotational angle.
 18. A method according to claim17, wherein the step of determining the orientation of the product isperformed by means of a vision based technique.